Error stack traces should be printed out for syntax errors

[briandipalma]

Expected behaviour

Syntax errors that prevent any tests being should have their stack traces printed.

Actual behaviour

Syntax errors that prevent any tests being run don't have their stack traces printed.

Environment Details

• Karma version (output of karma --version): 1.7.0
• Relevant part of your karma.config.js file

Steps to reproduce the behaviour

1. Add nonsense variable lol to the top level of any test module.
2. Watch it fail.
3. Feel sadness at the lack of stack trace in the error logging.

PR incoming.